A promising cooperation of photocatalysis and electro-floatation for treatment of eutrophicated raw water

In this study, a coupling process of photocatalysis and electro-floatation was developed for removing algae and organic matters in eutrophicated raw water. A series of processes, such as individual photocatalysis, individual electro-floatation, photocatalysis and electro-floatation (combined process), were constructed to explore the effect on removing pollutants with these process and probing interaction mechanism of photocatalysis and electro-floatation. Results showed that the removal rate of soluble chemical oxygen demand (SCODMn), total chemical oxygen demand (TCODMn), and chlorophyll a (Chl-a) through individual photocatalysis process are 55%, 14%, and 30%, and the removal rate of above indicators through combined process are increased to 91%, 70%, and 86%. Furthermore, the presence of electro-floatation can improve the photocatalytic activity of photocatalyst, which attributes to that electro-floatation can supply abundant O2 which is beneficial for Bi4O5I2([Hmim]I)/Bi4O5I2(KI) photocatalyst to generate more active species (•O2−), as well as generate abundant floating microbubbles to enhance the mass transfer of pollutants and photocatalysts. This study will provide a new idea for the efficient treatment of algae and organic matter simultaneously from eutrophicated raw water and provide guarantee for in-situ eutrophication restoration of water body.